Composite articles are manufactured by injection molding of synthetic resins over an insert made of another material, most often metal, and disposed in the mold. These articles combine useful properties of the constituent materials, for example strength of a metallic reinforcing member with insulation or pliability of a plastic coating.
U.S. Pat. No. 5,160,772 describes integrally molded lightweight composite articles having a foam core, a metallic supporting element encapsulated in the foam core, and a rigid outer layer (shell) of polymer around the core. The articles are formed by placing a foam core having an integral outer skin in a mold and polymerizing a monomer around the core.
JP03036008 discloses a composite article and a molding method where two metallic plates are arranged with a space between them in a mold. The space is then filled with synthetic resin to form a core layer. The metallic plates have openings and the mold has corresponding hollows which are also filled, so that protrusions may be formed integral with the core layer.